1. Field of the Invention
This invention relates to a laser coagulation system, and more particularly to a laser coagulation system adapted for use in an ophthalological treatment in which a laser beam from a laser source is radiated into a patient's eye to develop a large amount of heat effective to cause thermal coagulation at a predetermined portion of the biological organism in the eyeball of a patient.
2. Description of the Prior Art
There have long been known laser coagualtion systems in which during an opthalmic operation against diseases such as retina detachment, glaucoma, etc., a patient's eye is irradiated with laser energy, which is absorbed in a biological organism such as retina to develop thermal coagulation thereon for ophthalmological treatment. For this purpose, the laser coagulation system includes a laser beam projector for producing a laser beam from an argon or krypton laser, which is condensed to a laser beam of a predetermined diameter, directed toward a predetermined portion of the eyeball to be coagulated, and then focused thereon as a laser spot for thermal coagulation.
The laser coagulation system further comprises a slit image projector for forming a slit image on the eyeball to illuminate the background and to determine the predetermined portion of eyeball to be coagulated.
This type of laser coagulation system is further provided with an observation equipment for observing the slit image and the laser beam projected onto the eyeball to be coagulated. Doctors always observe the eyeball by means of the observation equipment to be able to accurately perform the laser beam projection onto the eyeball to be coagulated. Some of the laser beam is usually reflected back from the irradiated eye portion into the eyes of the doctor through the observation equipment, thus resulting in damage to his eyes.
To prevent such damage, a safety filter is provided to absorb laser energy reflected into the observation equipment.
On the other hand, it has become very typical to selectively employ two different laser beams such as argon and krypton laser beams depending upon the eye portion to be treated. Thus, two kinds of safety filters respectively corresponding to the argon and krypton laser beams are necessary.
Therefore, the prior art coagulation system has the drawback that the safety filter corresponding to the laser beam being used must be attached to the observation equipment every time it is used. This can eventually lead to a big problem in that the selection of the wrong safety filter can cause a serious injury.